Dihydromyricetin ameliorates chronic liver injury by reducing pyroptosis

BACKGROUND: Chronic liver injury (CLI) is now a worldwide disease. However, there is no effective treatment. Pyroptosis plays an essential role in CLI. Dihydromyricetin (DHM) resists oxidation and protects the liver. We hypothesize that the beneficial effect of DHM on CLI is related to its effect on the expression of pyroptosis-related molecules. Therefore, we studied the influence of DHM on CLI and pyroptosis. AIM: To study the role of pyroptosis in the pathogenesis of CLI and the therapeutic mechanism of DHM. METHODS: Thirty-two mice were randomly divided into four groups: The control group was injected with olive oil, the carbon tetrachloride (CCl(4)) group was injected with CCl(4), the vehicle group was injected with hydroxypropyl-β-cyclodextrin while injecting CCl(4) and the DHM group was injected with DHM while injecting CCl(4). After four weeks of treatment, liver tissues from the mice were stained with hematoxylin and eosin, and oil red O. Blood was collected from the angular vein for serological analysis. The severity of CLI was estimated. Some liver tissue was sampled for immunohistochemistry, Western blotting and quantitative reverse transcription PCR to observe the changes in pyroptosis-related molecules. RESULTS: Serum total cholesterol, low density lipoprotein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the CCl(4) group were higher than those in the control group, and serum total cholesterol, low density lipoprotein, AST and ALT in the DHM group were lower than those in the vehicle group. Hematoxylin and eosin and oil red O staining showed that there were more lipid droplets in the CCl(4) group than in the control group, and there were fewer lipid droplets in the DHM group than in the vehicle group. Western blotting showed that the expression of the pyroptosis-related molecules caspase-1, NOD-, LRR- and pyrin domain-containing 3 (NLRP3) and gasdermin D (GSDMD)-N in the CCl(4) group was higher than that in the control group, while expression of these proteins in the DHM group was lower than that in the vehicle group. Quantitative reverse transcription PCR results showed that the expression of the pyroptosis-related genes caspase-1, NLRP3, GSDMD and interleukin-1β (IL-1β) in the CCl(4) group was higher than that in the control group, while there was no significant change in NLRP3 and caspase-1 expression in the DHM group compared with that in the vehicle group, and the expression of GSDMD and IL-1β was decreased. CONCLUSION: DHM improves CCl(4)-induced CLI and regulates the pyroptosis pathway in hepatocytes. DHM may be a potential therapeutic agent for CLI.